Influence of Water Depth on the Peak Overpressure and Energy of the Secondary Pressure Wave of Underwater Explosions

In this study, experiments for underwater explosions at water depths of 100-600 m were carried out in a pressure tank using 1 g RDX charge (cyclonite). The peak overpressure and energy of the secondary pressure wave (SPW) at different water depths were obtained, and their relationships with the water depth were analyzed. Using AUTODYN software, a numerical model of the underwater explosion was established, and the experimental data were used to verify the effectiveness of the model and the reliability of the simulation results. Then the peak overpressure and energy of SPWs in underwater explosions were calculated under 19 water depth conditions (2-8000 m) with 10 measurement points in each condition. The characteristics of the SPW were analyzed. According to the explosion similarity law, calculation models for the peak overpressure and the energy flux density with a water depth correction coefficient were established. The results showed that with the increase of the water depth, the energy of the SPW decreased, and the peak overpressure increased at a gradually decreasing rate. At different water depths, the peak overpressure and the energy flux density of the SPW conformed to the explosion similarity law, showing that the established models have reliable practicability and extensive expansibility in engineering.